Back in the late 90s (eons ago) I tried a variety of passive preamps (PPs). The most musical was an autoformer, but back then my system was not balanced. For the last decade I have been using active preamps, both tube and solid state, but finding a quality balanced preamp under $4K is damn near impossible. Enter the Parasound P5 (2.1), which in addition to having balanced I/Os, it has a separate bass management circuit (MSRP $1095), and I was hoping it would provide better control over the built in class D plates incorporated into my 2 SVS powered subs, whose volume controls are STUPIDLY sensitive: when barely cracked from zero they overwhelm. Alas, no bueno.
Recently i watched a PS Audio YT video that was emphatic about NOT connecting powered subs with interconnects; instead he recommends speaker cables piggybacked off the main systems amp/s. I had a spare set of DIY flat copper cables, and was shocked how much better they sounded, but doing so did not change the volume control problem and unfortunately this id not bypass the SVS amps whose class D chips are now ancient. Thinking there could be an impedance problem led me to revisit PPs.
I sold my P5 and was using the XLR outs from my Oppo 105 (upgraded power supply and IEC/wiring to the power supply) direct to my Emerald Physics 100.2SEs (class D). The noise floor dropped tremendously, allowing me a much better view into the music. My Core Power Technologies 1800 PLC had more than a little to do with this, but...
Days of PP research later, I came across LDRs, which seem like the ultimate PP option, but XLR versions are ~ $2K and up, with the Tortuga coming in at $2700, seems like a true SOTA bargain, just not in my current budget. Scouring the' for sale' sites I came across a Hattor XLR (MSRP $995) which was in my price range. Hattor's www had links to 2 reviews both were extremely positive: one used it in combination with a class D amp. Bingo! I snapped it up.
It arrived late yesterday, although Hattor's www pictures look awesome, they do not compare to seeing and touching it. The metal carrying case was an indication of the designer's dedication. This is an etremely well made piece of kit, but how does it sound? Alas it came with no manual and Hattor's site does not have a PDF. How hard can it be to hook up? Well, after a couple scary minutes, I discovered that it would not light up until I connected the 105.
Stone cold, the first thing that shocked me was a further reduction in noise floor and an incredibly wide and deep sound stage, but as can be expected, it was dry. Fingers crossed, in about a half hour I began to be rewarded with texture as well. Tis only got better as the night wore on
I hope somebody chimes in with their Tortuga experience, or any other high quality PP information.that goes under the reporting radar.
George, your info would be spot on IF the AA did not have 2 gain options (I was unaware how valuable that is). I didn't try the base gain until late last night: where did the music go? I quickly reengaged the + 6dB and viola. Im a very happy camper again. And I am not abe to use (and not missing) my 2 SVS Ultra powered subs, which is more evidence of the EP/Hattor mismatch
Eventually the Hattor will go to a new home, to be replaced by either an AA DDP-1 (but I don't need either the dac or the headphone circuit) and if the dac is better than in my Oppo 105 I'm guessing I would need to switch it in/out when listening to non SACD format:and if so, no bueno, but I think I can get one with power supply in the $1500 range. If so, I probably will. So far the Tortuga LDRxB is at the top of my wish list, but it's $2700. I could stretch to half that amount, but don't see that happening :(.
I decided against the Nord for several reasons
* it would take 3-4 weeks and I was music-less * it had tons more power than my 94dB KCIIs need to jump out of the speakers, and my new speakers are 96db *
the AA
was almost half of the Nord price
First, my mnd is officially blown after replacing my Emerald Physics 100.2SE monos (with upscale fuses) with an Audio Alchemy DPA-1, (125w @ 8 ohms) Having 2 Gain options are crucial in my case; seems my Hattor Passive needs the extra 6db to come on song, otherwise, meh! I am told AAs preamp/dac sounds as good as Constellations 1.0 @ ~ $2700 with external power supply, which is said to be essential
I suggest you read Absolute Sound reviews of the Constellation 1.0
Preamp ($9000); itself a lower cost version of their Inspiration preamp ($24000) and the Tortuga LDRXB passive $2695 vs the rest of the simplistic passive world. Not hatin, just sayin
Replacing resistor ladders with LED light tech requires an entirely different (and more complex) approach to passives. It's hard or me to imagine being "that' must better than my Hattor, but....
LDRs are not the easiest components to work with notwithstanding their superior sonic qualities. Their challenges are twofold. First, the relationship between LED current (light intensity) vs. resistance is inherently nonlinear. Secondly, even with LDRs of a given make and model there's considerable variance in this nonlinear relationship from one individual LDR to the next. To implement a reasonable stereo attenuator with LDRs means you have to use 2 per channel. Given both their nonlinear behavior and individual variances, you soon realize that you first have to test each individual LDR and record its current vs. resistance curve. All of that data goes into our LDR database where at any point in time we usually have test results for over 100 LDRs which we haven't already used. We've developed sorting routines that process this data to tell us which next 4 LDRs are most closely matched. If we decide those 4 aren't sufficiently close, we'll test another 50-100 LDRs and add them to the database, then re-run the sort until we get satisfactory matches.
So your advice is at best archaic, or limited to your investigations
It will also pass clean 1080p component video or coaxial 24/192 digital & DSD.
It might also pass a couple of amps of current at ~12vdc. All with the volume wide open, of course. High current DC and high MHz AC capable, all in the same box.
Let me rephrase that a bit. (deleted my above prior post) Wrote it too fast and slightly incomplete. Some capacity for AC, as in HF alternating current. More like ’RF capable’, would be the better analogy. Lowe current, low voltage, but Radio Frequency. Similar in bit bandwidth, as well. Very high bit bandwidth, essentially.
Tweak1 It may sound good, but I don’t want to burst your bubble, you should have asked, if your still using your Hattor passive, you didn’t heed what I said about your EP 100.2 amp being only 19kohm input impedance, and not the best match for your Hattor passive.
Now you bought the AA DPA-1 without looking at it’s input impedance, as it’s even lower and more difficult to drive than the EP was, at 17.0 kohm xlr and 10.7 kohms rca, this I hate to tell you it's a worse match for the Hattor than your EP was.
You said you were looking at the Nord Two Stereo amp, and I said this was better than the EP, should have stayed with that.
You have two options to get the best with what you have. 1:Send your Hattor back and get them to install the optional OPA2134 output buffer in into it, this will allow it then to drive the very low input impedance of the AA or the EP if you still have it. 2: Send the AA back and get a poweramp that has got higher input impedance 33kohm or higher.
After waiting at home all freakin day for my Audio Alchemy DPA-1 stereo amp
(had to sign), it showed up after 8pm. It only has ~ 100 hours, so a lot more break in awaits, BUT...
OMGosh, after about an hour for my entire system to warm up (sold my EP 100.2SEs about 3 weeks ago) I am hearing a much more complete musical experience. Think early digital (Perfect Sound Forever) and today's high resolution digital
Glimpses of being transported to the venue
My Emerald Physics KCIIs never sounded so good, but they are FS as I await their replacements
@tweak1 A buffer is an active stage that does give gain. Because it's assumed everything in an audio chain are voltage sources, voltage gain is all that gets labeled gain. Building pure current gain circuits is totally possible. That's what a buffer is. The output stage of a power amp is typically a massive current gain stage, i.e., a buffer, to the loudspeakers. Input stages to power amps are reactive loads. They have some inductance, impedance, and capacitance. That's why their behavior drifts around depending on the signal frequency. Flatly assuming a 10:1 impedance match is all that needs considered is simplistic to say the least. All reactive loads will induce some nonlinearity in the driving gain devices. If those devices aren't in the pre-amp, then they're in the source. Hope that makes some sense.
I have been using an EVS attenuator for several years. It also affords the benefit of only one interconnect, although it is a pain to reach behind to adjust the volume. I am, wow not hearing any restrictions through my100k Llanodesign. The passive sounded a bit more transparent than my previous. Plus I have a tube voltage stage, so I pick up that benefit.
1graber2 @georgehifi : in addition to the Schiit you listed above, there now is the Schiit Freya PreAmp: its a real "swinger": can play as 1. Passive Pre 2. Active Pre with tubes 3. JFET buffer
Yes I know, if you look at my posts going back for the last year, I think I'm probably the strongest promoter of the Freya for 3 in one preamp at a steel of a price.
I think the Passives are coming of age: more notoriety, more companies, more tech used (eg. Tortuga Class D passives), and now multiple $300 passive preAmps on eBay from China, which are probably pretty good.
@georgehifi : in addition to the Schiit you listed above, there now is the Schiit Freya PreAmp: its a real "swinger": can play as 1. Passive Pre 2. Active Pre with tubes 3. JFET buffer
So, you wanna find out how passive works? get the Freya, and toggle b/w the 3 power options to be able to hear the differences in real time! Its only $700, 30 day trial period, 5 year warranty, and designed and mostly built in the US. What is not to like?
But for my entry-level high end system, I would try out the Music First passives Pre's. Ive heard them repeatedly at trade shows- very impressive.
Fun anectdote: One year as CAS, the owner of Music First had a room. He had transferred a CD copy of the Jackson 5 to a 1/4" tape, played it via a tape to tape player (modest, not high end), running into a Music First Passive pre, into a Bel Canto S300 Class D integrated into an old pair of Rogers bookshelf speakers ( that I think he bought in the States when he arrived in CA for the show. You'd be surprised how good it sounded!)
No they have not. What in you imagination could make them offer less then they do
You have not referenced your statement to any post, so it means nothing. BUT IF it is to the post above yours, then I’m afraid you clearly have no idea what talking about.
Scratching my head as George said my Hattor is not compatible impedance wise
It’s not the fault of your Hator, it’s the amp that is only 19kohm input impedance, even the Khozmo is not compatible. They (Hattor& Khozmo) would both have to be 1-2kohm pots to be compatible with 19kohm, then the source would have trouble driving into that 1-2kohms.
I just found this out reading my Hattor is a review. Scratching my head as George said my Hattor is not compatible impedance wise
The guy responsible for the Khozmo passive also makes an upmarket version (ed Hattor) with super-duper resistors, balanced inputs and outputs, a balance control, a nice remote and a buffer circuit.
Tortuga does offer a tubed buffer. I tried it on their "tour" and it sounded pretty good. My Goldpoint passive along with the Tortuga buffer did not quite equal my SMc Audio unity gain buffered preamp, but the SMc piece is much more expensive.
From Tortuga Audio
Our 30 day audition policy provides you a nominal 30 day window to audition any Tortuga Audio product. If you are not satisfied with your Tortuga Audio product just return it within 30 days of receipt of the shipment and we will refund the full purchase price. No questions asked.
tweak1OP I have been keen on getting a Nord Two Stereo amp, but need to sell at least one SE first
This will be great with your
Hattor Passive Pre and much better. As the Nord is double the input impedance of the
Emerald Phyics no need for a buffer then. I always say the best buffer is no buffer if possible.
Hi tweak1, I`ve been using the Tortuga LDR for awhile now and I`m enjoying it very much.
I added an inexpensive tube buffer (Yaqin CD-3) to help with impedance matching after pulling out my Rogue Tube amp and putting in an ATI SS amp in its place.
I did it for fun, as I absolutely loved the Rogue and it has been a stellar performer. I listen at a lowish volume level but I just wanted to hear what a hefty amp would do for my Revels. The Tortuga, Yaqin combo sounds very clean and clear and the front panel volume display numbers on the LDR have dropped quite a bit which seems to show everything is playing nicely together...very please !!
Thanks George. While the combo sounds vg, there is something eating at me. Not sure whether it's the amps or the speakers. I own EP KCIIs, but bought a pair of demo EP 3.0s Alas, there have been weird issues involved in them being delivered. I have been keen on getting a Nord Two Stereo amp, but need to sell at least one SE first
Actually hate to say, your Emerald Phyics EP-100.2SE Class-D amps are not a great match for a passive pre, as their input impedance is "not typical" as they are very low at 19kohm, your passive preamp while working fine would sound even better if it had a unity gain buffer on it’s output. For a 10kohm passive to work it’s magic the input impedance of an amp/s should be 33kohm or higher.
Well, I have been living with my Luminous Audio Axiom II for a week now. It is the top single ended unit : Walker mod, 3 in, 2 out, with remote. I can honestly say I have reached a point where I am hearing " everything " within the recordings. I can better connect with the artistry of the musicians and, the work of the recording and mastering engineers. It is an open window, unaltered, allowing me to hear it all as I believe it should be. I will report further as time goes on, but so far, I am very lucky with the synergy, and even happier with the outcome. Enjoy ! MrD.
Thanks, I wasn't asking for myself as my Hattor Passive Pre is quite magical with my class D amps. But being such a clear window I think it exposed that my speakers or amps (or both) are not up to it. My EP KC IIs sound fantastic until pushed in my 19 X 36 x 12 open beam ceiling room; and I have 2 SVS Ultra subs!
I am in high anticipation of receiving EP 3.0s with 12" compressed driver, which I hope adds sufficient lower mids/upper bass to compensate for the room
If you look around, you might find a review of passive vs active, where the specific passive unit in question and it’s unique technology... trounces all active and all other passive, in dozens of systems tried.
So the synergy question is answered ....and goes away.
Its all about achieving system synergy active passive buffer all can be used in proper system and can achieve synergy but I would say passive types take more thought and also have more chance of disrupting synergy. At this time I have a art audio pre its active or passive I have the cheap schitt and a costly line magnetic trans based about. If passives synergizing you get a bit less colored sound with improvements to image and detail if active you get improvement in bass drive and dynamics. I have owned a good num of other active pres and passive types and I tend to prefer a trans based if rest of systems up to it.
Quite easy, just look at your specs of your source and your amp. Or if you have difficulty in doing that just post the brand and model of your source/s and amp up here, I will look them up for you. A I’ll give in detail what they are doing. Cheers George
1. I believe NPass is speaking to a perfect electronic interface world, which would necessitate building ones system around a PP, as opposed to trying to insert one into a active preamp system
I believe it does, and that "perfect electronic interface" is available in systems much much more than not.
1: If the source has more output voltage than the amp has input sensitivity to give full output. This is maybe in 100% of cases. (I have yet to see a source with less output voltage than the amp needs input voltage to make it clip)
2: The ratio of output impedance to input impedance, of the source to passive and from the passive to the amps, are both 1:10 ratio or more, this also would be in at least 90% of cases.
Then you have what you call, that "perfect electronic interface" for a passive to work as it should, which is getting the source signal to the amps in the most transparent, undistorted, uncoloured, unhindered way.
1. I believe NPass is speaking to a perfect electronic interface world, which would necessitate building ones system around a PP, as opposed to trying to insert one into a active preamp system
2.. A quality PP, such as the Hattor, is a high powered microscope, exposing whether there is/are problems/issues elsewhere in the chain.
I feel that my Emerald Physics amps are the next step in my progression, I am close to pulling the trigger on a Nord Two SE Power Amp (newest class D tech), and .I have the next model Emerald Physics Speakers (3.0) with cap upgrade and WireWorld internal wiring on the way (I think, as they were supposed to be hear almost 2 weeks ago)
I think TVCs are the way to go passively and don't experience the loss of dynamics,
TVC's are also great, but they do have their own colouration if you don't mind that, as that poor weak source signal has to go through a "mile" of very thin transformer wire winding and back out again, they are not as transparent to the source as other passives. Plus never get one with "gain" stay with unity, as they do have a tenancy to "ring" from the test we've seen.
I think TVCs are the way to go passively and don't experience the loss of dynamics, etc. that resistor-based passives bring. I compared my Music First to several active, tube preamps and it was the champ.
When you they want to know several things about what you listen with, so the passive preamp can have its impedance matched to your particular system.
If using a ladder network (no.2), the best, this is a bit of a sales gimmick, a 10kohm passive is what’s needed for most. EG: The only time I can see say a 50 or 100kohm passive being needed, is if the source has an output impedance of over 5kohm (yuck!) and the poweramp amp happens to be maybe a Rogue that has 1 megohm input impedance.
If they use just a fixed series resistance and vary the shunt resistor (no.3) to ground, which is not as good as the ladder, then yes they can sort of tune it a bit better for different conditions, but this shunt series method varies wildly in it’s I/O impedance, unlike the ladder far more stable. I think you’d be better off just using an Alps Blue Velvet (RK27) or Alps Black Beauty (RK40) at 10kohm. See linked diagram.
Impedance mismatching is a problem that will leave an otherwise great passive preamp sounding less than it should. Why I did not see anyone here mention the Luminous Audio Axiom? When you they want to know several things about what you listen with, so the passive preamp can have its impedance matched to your particular system.
With almost a week in use, and a wide variety of favorite music spun, the biggest issue I have is that it is doing it's job too well. In part, due to the lack of overdesign, and quality resistors, it ruthlessly exposes when recordings are subpar.
Examples of well known artists: Dixie Chicks, John Denver, CSN, Dr John, all contain some excellent recordings as well as some really horrible ones. How can that be?
Interesting coincidence, Paul McGowan posted a PP YT video yesterday
using active or passive PP is definitely a personal choice basis on own sensibility and perceptions. Anyway PP should be simple, minimalist, few components but highly selected, maching and quality, good pcb, psu, connectors, knobs, selectors... if possible non condensers into the routing of music. As said in other forum, “PP, like a good steward, shall just manage the inputs and main volume, normalize in and out impedances and gain between inputs, nothing else, bringing the music “as it is” from source to the amplifier “. In this philosophy PP should be reasonably expensive but not exaggerating being more expensive than a more complex source or amplifier... all the rest are reclame and business for peoples abusing of our enthusiasm. I prefer active PP because never should be lack of “food” to the amplifier, especially when sound is so dinamic. Have a pleasant sound session, regards
mrdecibel
I so much prefer no preamp.
I am currently shopping for a passive, with multiple inputs, as the amp I would like to use is very high gain ( it was designed to be used with the source voltage driving it ). It is likely I will never use a preamp again. Enjoy ! MrD.
MrD you want a 10kohm passive, as that will serve most situations, as most s/s sources can drive 10kohm no problems, and a 10kohm pot has at worst around 2.5kohm output which will drive almost all poweramps >33kohm input.
1: For the cheapest option, you could go Schiit Sys, for $49 it’s 10kohm with 2 inputs one output. http://www.schiit.com/products/sys 2: Then there the Saga which is 10kohm passive with a better relay pot and it has output tube output select’able if desired 5 inputs two outputs. http://www.schiit.com/products/saga 3: There are a few LDR some passive including mine which mimics a 10kohm pot.
A couple of things. Looking around, more and more integrated amps, and similar products, are bypassing having a preamp section altogether, taking the source and switching, only, into the amp stage. My top of the line Sony cd player, many years ago, mention in the owners manual, to go from the variable out, into the power amp. This " passive " thing is not new, and it is gaining momentum each day. About a week ago, I decided to bypass my preamp and come straight out of my fixed level dac, and specifically used a lower wattage, pro Yamaha amp, with it"s input level controls. Using my Sheffield Labs Drum Record, I so much prefer no preamp. I am currently shopping for a passive, with multiple inputs, as the amp I would like to use is very high gain ( it was designed to be used with the source voltage driving it ). It is likely I will never use a preamp again. Enjoy ! MrD.
@georgehifi I believe facts. Facts like Nelson Pass explaining the superiority of a buffer to a passive. Facts like measured performance. Facts like subjective performance. Facts like the rarity of passives.
@georgehifi Nonsense. Active pre-amps aren't going anywhere. They're an unusual fetish that'll never become mainstream because of their unavoidable failings. 5000 ohm of impedance to the input of 90% of amps is never going to sound as good as 50 ohm.
One way to find out which you like better (i.e., pure passive or passive with an active buffer circuit) would be to purchase the Hattor or Tortuga passive and then add their buffer. Tortuga offers a 30-day return policy in the event you like the sound better without the buffer.
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